ABSTRACT
Background: Repeat sports-related concussive/subconcussive injury (RC/SCI) is related to memory impairment.
Objective & Methods: We sought to determine memory differences between persons with RC/SCI, moderate-to-severe single-impact traumatic brain injury (SI-TBI), and healthy controls. MRI scans from a subsample of participants with SI-TBI were used to identify the neuroanatomical correlates of observed memory process differences between the brain injury groups.
Results: Both brain injury groups evidenced worse learning and recall in contrast to controls, although SI-TBI group had poorer memory than the RC/SCI group. Regarding memory process differences, in contrast to controls, the SI-TBI group evidenced difficulties with encoding, consolidation, and retrieval, while the RC/SCI group showed deficits in consolidation and retrieval. Delayed recall was predicted by encoding, with consolidation as a secondary predictor in the SI-TBI group. In the RC/SCI group, delayed recall was only predicted by consolidation. MRI data showed that the consolidation index we used mapped onto hippocampal atrophy.
Conclusions: RC/SCI is primarily associated with consolidation deficits, which differs from SI-TBI. Given the role of the hippocampus in memory consolidation and the fact that hyperphosphorylated tau tends to accumulate in the medial temporal lobe in RC/SCI, consolidation deficits may be a cognitive marker of chronic traumatic encephalopathy in athletes.
Author Contributions
Study concept and design: M.J.W.; data acquisition and analysis: M.J.W., D.F.K., K.G., D.J.H., P.M.V., D.A.H., W.D.L., M.M.M., E.S.L.; drafting manuscript and figures: M.J.W., M.M.M., E.S.L.; review and editing the manuscript: M.J.W., M.M.M., E.S.L., P.Y.L., D.J.H., D.F.K., K.G., R.C.C., P.M.V., D.A.H., W.D.L., C.W., R.S., J.M.F.
Competing of Interests
We declare no competing of interests.
Data availability
Data from this study will be made available upon request to M.J.W.